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1. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 08 | Aug 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1333
A Study on Use of Recycled Aggregate in Standard Mix Design & its
Sustainibility
Annapurna Kumari Tazan
M. Tech Student, Structural Engineering, MM College of Engineering & Technology, Chhattisgarh, India
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Abstract – Waste management industry moves around the
collection, storage and waste disposal. A waste management
system is a process of treating waste which consists of
collection, recycling and disposal or waste processing.
Recycling, reuse, combustion and landfill methods helps in
reducing waste. Waste disposal is a major issue especially in
the field of construction industry. Landfilling method is
cheaper and easiest among all but finding land for it is getting
difficult. NR protection is the first priority.
Thus recycling and reuse can reduce construction and
demolition waste. This will help in conservation of NA for next
generation. The main objective is to save environment and
resources both. For reaching above objective mentioned steps
are to be followed for making RCA, first collection of
demolished waste. Second addition of collected waste to NAin
different proportions. Third, RCA produced will be tested for
different parameters. Finally, it is analyzed for its application.
The study is dealing with the usage of RCA in standard mix
design and involves validation of NC formed based on
concrete test results. These test results is helpful in determing
its application in different constructions. Itsusewillreducethe
percentage of NA in construction without compromising the
quality of concrete. Also its contribution on environment
protection and sustainability.
Thus, this project gives a brief idea about need of recycling of
aggregates and benefits of RCA in comparison with the NA.
Contractors must turn their focus in spending in recycling
which in turn helps in conservation of NA.
Key Words: Recycling, Reuse, NR-natural resource, NA-
natural aggregate, RCA- recycled concrete aggregate,
sustainability.
1. INTRODUCTION
Researchers have conducted some researchesfrom10years
ago, related to recycled aggregates to be used in concrete
roads, pavements, bridges, etc. however, they have not
applied recycled aggregates for structural concrete. The
purpose of this research is to use recycled aggregate for
structural concrete in Raipur (C.G). The reason of selecting
Raipur(C.G) for this study is this city is now more concerned
for itsenvironmental conditions & waste management. This
chapter focuses on previous research studies about
environmental issues, waste management and Recycled
Aggregate Concrete (RAC).
Fig:1
1.1 Natural Aggregates
Natural aggregates, which consist of crushed stone andsand
and gravel, are among the most abundant natural resources
and a major basic raw material used by construction,
agriculture, and industriesemploying complexchemicaland
metallurgical processes. Coarse aggregates are particles
greater than 4.75mm, but generally rangebetween9.5mmto
37.5mm in diameter. Fine aggregates generally consist of
natural sand or crushed stone with most particles passing
through a 3/8-inch sieve.
1.1.2.Properties
1.1.2.1. Absorption, Porosity & Permeability
The internal pore characteristics are very important
properties of aggregates. The size, the number, and the
continuity of the pores through an aggregate particle may
affect the strength of the aggregate, abrasion resistance,
surfacetexture, specific gravity, bonding capabilities, and
resistance to freezing and thawing action.Absorptionrelates
to the particle'sability to take in a liquid.Porosity is aratioof
the volume of the pores to the total volume of the particle.
Permeability refersto the particle's ability toallowliquidsto
pass through.

2. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 08 | Aug 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1334
1.1.2.2. Surface Texture
Surface texture is the pattern and the relative roughness or
smoothness of the aggregate particle. Surface textureplaysa
big role in developing the bond between an aggregate
particle and a cementing material. A rough surface texture
givesthe cementing material something to grip, producinga
stronger bond, and thus creating a stronger hot mix asphalt
or portland cement concrete. Surface texture also affectsthe
workability of hot mix asphalt, the asphalt requirements of
hot mix asphalt, and the water requirements of portland
cement.
1.1.2.3. Strength & Elasticity
Strength is a measure of the ability of an aggregate particle
to stand up to pulling or crushing forces. Elasticity measures
the "stretch" in a particle. High strength and elasticity are
desirable in aggregate base and surface courses. These
qualities minimize the rate of disintegration and maximize
the stability of the compacted material. The best results for
portland cement concrete may beobtainedbycompromising
between high and low strength, and elasticity. This permits
volumetric changes to take placemoreuniformlythroughout
the concrete.
1.1.2.4. Density & Specific Gravity
Density is the weight per unit of volume of a substance.
Specific gravity is the ratio of the density of the substance to
the density of water.
1.1.2.5. Aggregate Voids
There are aggregate particle voids, and there are voids
between aggregate particles. As solid as aggregate maybeto
the naked eye, most aggregate particles have voids, which
are natural pores that are filled with air or water. These
voids or pores influence the specific gravity and absorption
of the aggregate materials.
1.1.2.6. Hardness
The hardness of the minerals that make up the aggregate
particles and the firmness with which the individual grains
are cemented or interlocked control the resistance of the
aggregate to abrasion and degradation. Soft aggregate
particles are composed of minerals with a low degree of
hardness.
1.2 Recycled Aggregate
Recycled aggregate is produced by crushing concrete, and
sometimes asphalt, to reclaim the aggregate. Recycled
aggregate can be used for many purposes. Ex- fly ash, silica
fumes etc.
2. METHODOLOGY & WORK
The main aim of this study is to perform experimental
study to investigate the properties of concretes produced
with recycled aggregatesin Raipur (C.G) and comparisonof
them with normal concrete. During the experimental work,
different concrete samples with various concrete mix
designs were investigated.
For casting normal concrete samples, cement with grade 53
is used. Sand & boulders are used as fine and coarse
aggregate respectively. Drinkable water wasused as mixing
water.
For casting recycled concrete samples, same cement is used.
Recycled concretes with different strength levels (20-30
MPa) need to be crushed by jaw crusher and are separated
according to their size distributions. Two different concrete
samples will be casted. Cubic samples with the sizes of 150
mm and cylinder samples with the size of 100×200 mm are
chosen for compressive strength, non-destructive tests,
freeze-thaw resistance, and splitting tensile strength,
respectively. The natural curing condition is performed for
the samples. Compressive strength and splitting tensile test
are conducted at 7 days, 14 days and 28 days. Non-
destructive tests need to be done at 14 and 28 days and
freeze-thaw resistance tests will be done at 28 days.
Steps to be followed:
1. Structural concrete need to be crushed and sieve
analyses is done for both group of aggregates
(normal aggregates and recycled aggregates).
2. Water absorption test and specificgravityofnormal
and recycled aggregates are performed.
3. According to two different mix designs, materials
were mixed; concrete is made and poured into
forms and compacted; and the hardened concrete
samples are cured.
4. Compressive strength, splitting tensile strength,
PUNDIT, rebound (Schmidt) hammer and freeze-
thaw resistance of each sample is determined.
5. According to the test results, comparison between
normal concrete and recycled aggregate concrete
were performed.
2.1. Tests to be followed
2.1.1. Specific Gravity Test
The specific gravity of an aggregate is considered to
be a measure of strength or quality of the material. Stones
having low specific gravity are generally weaker than those
with higher specific gravity values.
Aggregate sample is washed thoroughly and immersed in
distilled water and a cover of at least 5cm of water abovethe
top of basket. The basket and aggregate should remain
completely immersed in water for a period of 24 hour
afterwards. The basket and the sample are weighed while
suspended in water.

3. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 08 | Aug 2018 www.irjet.net p-ISSN: 2395-0072
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The basket and aggregates are removed from water and
allowed to drain for a few minutes, after which the
aggregates are transferred to the dry absorbent clothes.The
empty basket is then returned to the tank of water jolted 25
times and weighed in water
The aggregates placed on the absorbent clothes are surface
dried till no furthermoisture could be removed by thiscloth.
Then the aggregates are transferred to the second dry cloth
spread in single layer and allowed to dry for at least 10
minutes until the aggregates are completely surface dry.
The aggregate is placed in a shallow tray and kept in an oven
maintained at a temperature of 110° C for 24 hrs. It is then
removed from the oven, cooled in an air
Specific gravity = (dry weight of the aggregate /Weight
of equal volume of water)
2.1.2. Slump Test
The concrete slump test measures the consistency of
fresh concrete before it sets. It is performed to check the
workability of freshly made concrete, and therefore theease
with which concrete flows. The slump test is used to ensure
uniformity for different loads of concrete under field
conditions.
The test is carried out using a metal mould in the shape of a
conical frustum known as a slump cone that is open at both
ends and has attached handles.This cone is filled with fresh
concrete in three stages. Each time, each layer is tamped 25
times with a metal rod. At the end of the third stage, the
concrete is struck off flush with the top of the mould. The
mould is carefully lifted vertically upwards, so as not to
disturb the concrete cone.
The concrete then slumps (subsides). The slump of the
concrete is measured by measuring thedistancefromthetop
of the slumped concrete to the level of the top of the slump
cone.
2.1.3. Compressive Strength Test
Test for compressive strength is carried out either on cube
or cylinder.For cube test two types of specimens either
cubes of 15cm X 15cm X 15cm or 10cm X 10cm x 10cm
depending upon the size of aggregate are used.Thisconcrete
is poured in the mould and tempered properly so as not to
have any voids. After 24 hours these moulds are removed
and test specimens are put in water for curing. The top
surface of these specimen should be made even and smooth.
This is done by putting cement paste and spreading
smoothly on whole area of specimen.
These specimens are tested by compression testingmachine
after 7 days curing or 28 dayscuring. Load shouldbeapplied
gradually at the rate of 140 kg/cm2 per minute till the
Specimens fails. Load at the failure divided by area of
specimen gives the compressive strength of concrete
2.1.4 SplitingTensileTest
Splitting tensile strength test on concrete cylinder is a
method to determine the tensile strength of concrete. The
wet specimen is taken out from water after 7 days of curing
& wateris wiped out from the surface of specimen. The
weight is noted down and dimension of the specimen. The
compression testing machine is set for the required range.
Place the other plywood strip above the specimen. The
upper plate is brought down to touch the plywood strip &
the load is applied continuously without shock at a rate of
approximately 14-21kg/cm2/minute(Whichcorrespondsto
a total load of 9900kg/minute to 14850kg/minute) the
breaking load(P) is noted down.
2.1.5. Ultrasonic Pulse Velocity Test
Structural defects causes serious damages & collapses.
Ultrasonic testing provides information on the strength &
uniformity of concrete and can be used to detect voids,
cracks and defects. A pulse of ultrasonic (> 20 kHz)
longitudinal stress waves is introduced into one surface of a
concrete member by a transducer coupled to the surface
with a coupling gel or grease. The pulse travels through the
concrete and is received by a similar transducer coupled on
the opposite surface. The transit time of the pulse is
determined by the instrument. The distance between the
transducersis divided by the transit time to obtain the pulse
velocity. The longitudinal pulse velocity, Cp, of an elastic
solid is a function of the elastic constants (modulus of
elasticity, E, and Poisson’s ratio) and the density, ".
CP = [E(1-v) /p(1+v)(1-2v)]
2.1.6. Rebound (Schmidt) Hammer Test
Procedure for rebound hammer test on concrete structure
starts with calibration of the rebound hammer. After the
rebound hammer is tested for accuracy on the test anvil, the
rebound hammer is held at right angles to the surface of the
concrete structure for taking the readings. Six readings of
rebound number is taken at each point of testing and an
average of value of the readings is taken as rebound index
for the corresponding point of observation on concrete
surface.
2.2. Casting Concrete
According to British Standards,the process of batching,
weighting and mixing of required materialswereperformed.
First, aggregates and cement were mixed with mixer for 30
seconds, and then water was added and mixed for almost 3
minutes. For slump test, sample was taken from fresh
concrete, test was conducted and then, sample of fresh
concrete waspoured back to the mixer for remainingmixing
and finally moulds were filled
2.3. Compacting and Curing
After casting and compacting concrete samples, the samples
were placed to curing room with more than 90% moisture

4. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 08 | Aug 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1336
and 21°C temperature for 24 hours. Then,sampleswere put
into the water tank and kept until testing ages of 7, 14 and
28 days.
3. Results & Discussion
The experiments performed were consisted of specific
gravity, slump, rebound hammer test, compressivestrength,
splitting tensile test.
3.1. Slump Test
Slump test was conducted for each mix design.
Table1: Slump
Mix Design Slump(cm)
A 15
B 14
C 14
D 13
3.2. Compressive Strength
This test was performed on the cubic samples at the ages
of 7, 14 and 28 days. A comparison of recycled concrete
compressive strength results with normal concrete
compressive strength results.
3.3.Split Tensile Test
0
1
2
3
4
5
7th
day
14th
day
28th
day
Normal agg
Recycled agg
3.4. Rebound Hammer test
0
5
10
15
20
25
30
35
40
7th
day
14th
day
28th
day
Normal agg
Recycled agg
3.4. Ultrasonic Pulse Velocity test
0
1
2
3
4
5
7th
day
14th
day
28th
day
Normal agg
Recycled agg
Following observations were made based on abovetestresults
Table2: observation
Tests Applied Comparision
Slump High water demand in RCA
Compressive Strength RCA>NAC slightly
Split Tensile Strength RCA<NAC(10%)
Rebound Hammer test RCA<NAC(15%)
Ultrasonic pulse velocity RCA>NAC(12%)
3. CONCLUSIONS
Recycled aggregate concrete was the focus of this study.
Concrete samplesfrom MaterialsofConstructionLaboratory
of Civil Engineering Department NIT Raipur were crushed.
After sieving the crushed concretes,different mixes with
natural aggregates and crushed aggregates were designed.
Normal concrete and recycled aggregate concrete samples
were cast, cured, and tested. Different testsweredoneonthe
samples including compressive strength, splitting tensile
strength, PUNDIT, and rebound hammer. Based on the
obtained results and the influence of normal and recycled
aggregates on strength, porosity, and density, the following
conclusions and suggestions were mentioned.

5. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 08 | Aug 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1337
1- The numerical value of RCA slump was less than NAC
slump due to high water absorption percentage.
2- Compressive strength of recycled aggregate concretewas
slightly greater than normal aggregate in which the volume
of cement was held constant.
3- Splitting tensile strength of recycled aggregate concrete
was 10% less than normal aggregate with the same cement
volume.
4- The rebound hammer test results of recycled aggregate
concrete was 15% less than normal aggregate concrete
because the maximum size of recycled aggregateandnormal
aggregate was 23(mm) and 20(mm), respectively.
3.1 Advantages
Based on their physical and chemical properties and the
influence of normal and recycled aggregates on strength,
porosity, and density, the followingsustainibilitysuggestions
are mentioned:
1.Can be used for constructing gutters, pavements etc.
2.Large pieces of crushed aggregate can be used for building
revetments which in turn is very useful in controlling soil
erosion.
3.Recycled concrete rubbles can be used ascoarse aggregate
in concrete.
4.Production of RAC also results in generation of many by-
products having many uses such as a ground improvement
material, a concrete addition, an asphalt filler etc.
REFERENCES
[1]. Hansen, T.C. (1992), "Recycling of Demolished Concrete
Masonry.
[2]. Oikonomou,N.D.(2005)"Recycled Concrete Aggregates,"
Cement & Concrete Composites.
[3]. Thielen,G.(2004)"Concrete Technology Reports 2001-
2003,"German Cement Works Association.
[4]. US Deptt. of Transportation (2000) "Recycled Materials
in European HighwaysEnvironment-Uses,Technologiesand
Policies,".
[5]. Biojen,J. (1996) "Waste Materials and Alternative
Products "Pro's and Con's" Concrete for Environmental
enhanced and Protection.
[6]. Buchner, S. and Scholten, L.J. (1992). "Demolition and
Construction Debris Recycling in Europe," European
Demolition Association (EDA).
[7].“Solid waste management in Indian urban
centers,” International Solid Waste Association Times.
[8]. Mujahid and A. Zaidi, “Assessment of recycled aggregate
concrete.
[9].Rao, K. N. Jha, and S. Misra, “Use of aggregates from
recycled construction and demolition waste in
concrete,” Resources, Conservation and Recycling.